1. Field of the Invention
The present invention relates to novel cyclic diamine compounds which have inhibitory effects on both cell adhesion and cell infiltration and are useful as anti-asthmatic agents, anti-allergic agents, anti-rheumatic agents, anti-arteriosclerotic agents, anti-inflammatory agents or the like, and medicines containing such compounds.
2. Description of the Background Art
In various inflammatory diseases, infiltration of leukocytes into inflammatory sites is observed. For example, infiltration of eosinophils into the bronchus in asthma (Ohkawara, Y. et al., Am. J. Respir. Cell Mol. Biol., 12, 4-12 (1995)), infiltration of macrophages and T lymphocytes into the aorta in arteriosclerosis (Sakai, A. et al., Arterioscler Thromb. Vasc. Biol., 17, 310-316 (1997)), infiltration of T lymphocytes and eosinophils into the skin in atopic dermatitis (Wakita H. et al., J. Cutan. Pathol., 21, 33-39 (1994)) or contact dermatitis (Satoh, T. et al., Eur. J. Immunol., 27, 85-91 (1997)), and infiltration of various leukocytes into rheumatoid synovial tissue (Tak, P P. et al., Clin. Immunol. Immunopathol., 77, 236-242 (1995)), have been reported.
Infiltration of these leukocytes is elicited by cytokines, chemokines, lipids, and complements produced in inflammatory sites (Albelda, S M. et al., FASEB J., 8, 504-512 (1994)). Activated leukocytes adhere to vascular endothelial cells through an interaction called rolling or tethering with endothelial cells activated likewise. Thereafter, the leukocytes transmigrate through endothelium to infiltrate into the inflammatory sites (Springer, T A., Annu. Rev. Physiol., 57, 827-872 (1995)). In the adhesion of leukocytes to the vascular endothelial cells in this process, various cell adhesion molecules such as an immunoglobulin superfamily (ICAM-1, VCAM-1 and the like), a selectin family (E-selectin and the like), an integrin family (LFA-1, VLA-4 and the like) and CD44, which are induced on the surfaces of the cells by stimulation by cytokines or the like, play important roles (xe2x80x9cRinsho Meneki (Clinical Immune)xe2x80x9d, 30, Supple. 18 (1998)), and a relationship between the disorder state and aberrant expression of the cell adhesion molecules is noted.
Accordingly, an agent capable of inhibiting cell adhesion can be useful as an agent for preventing and treating allergic diseases such as bronchial asthma, dermatitis, rhinitis and conjunctivitis; autoimmune diseases such as rheumatoid arthritis, nephritis, inflammatory bowel diseases, diabetes and arteriosclerosis; and chronic inflammatory diseases. In fact, it has been reported that antibodies against adhesion molecules on leukocytes such as LFA-1, Mac-1 and VLA-4 or antibodies against ICAM-1, VCAM-1, P-selectin, E-selectin and the like on vascular endothelial cells, which become ligands thereof, inhibit infiltration of leukocytes into inflammatory sites in animal models. For example, neutralizing antibodies against VCAM-1 and VLA-4, which is a counter receptor thereof, can delay development of diabetes in an NOD mouse model which spontaneously causes the diabetes (Michie, S A. et al., Curr. Top. Microbiol. Immunol., 231, 65-83 (1998)). It has also been reported that an antibody against VLA-4 or ICAM-1 and its counter receptor, LFA-1, inhibits infiltration of eosinophils in a guinea pig and mouse allergic conjunctivitis model (Ebihara et al., Current Eye Res., 19, 20-25 (1999); Whitcup, S M et al., Clin. Immunol., 93, 107-113 (1999)), and a monoclonal antibody against VCAM-1 inhibits infiltration of leukocytes in mouse DSS-induced colitis model to attenuate colitis (Soriano, A. et al., Lab. Invest., 80, 1541-1551 (2000)). Further, an anti-VLA-4 antibody and an anti-CD44 antibody reduce the incidence of disease symptoms in a mouse collagen arthritis model (Zeidler, A. et al., Autoimmunity, 21, 245-252 (1995)). Even in cell adhesion molecule deficient-mice, inhibition of infiltration of leukocytes into inflammatory tissues is observed likewise in inflammatory models (Bendjelloul, F. et al., Clin. Exp. Immunol., 119, 57-63 (2000); Wolyniec, W W. et al., Am. J. Respir. Cell Mol. Biol., 18, 777-785 (1998); Bullard, DC. et al., J. Immunol., 157, 3153-3158 (1996)).
However, it is difficult to develop antibody-based drugs because they are polypeptides and so oral administration is a problem. Moreover, problems of the possible side effects due to antigenicity and allergic reactions are problems.
On the other hand, there have been various investigations of low-molecular weight compounds having an inhibitory effect on cell adhesion with a view toward permitting oral administration. These compounds include benzothiophene derivatives (Boschelli, D H. et al., J. Med. Chem., 38, 4597-4614 (1995)), naphthalene derivatives (Japanese Patent Application Laid-Open No. 10-147568), hydroxybenzoic acid derivatives (Japanese Patent Application Laid-Open No. 10-182550), lignans (Japanese Patent Application Laid-Open No. 2000-086641 through PCT route), condensed pyrazine compounds (Japanese Patent Application Laid-Open No. 2000-319277 through PCT route), 2,6-dialkyl-4-silylphenol (Japanese Patent Application Laid-Open Re-Publication No. 2000-509070 through PCT route) and the like. However, the goal has not often been sufficiently achieved under the circumstances. Cyclic diamine compounds described in Japanese Patent Application Laid-Open Nos. 9-143075 and 11-92382 do not exhibit a sufficient inhibitory effect on cell adhesion, and there is a demand for further improvement in activity.
An object of the present invention is to provide a substance having inhibitory effects on both cell adhesion and cell infiltration, plus excellent anti-asthmatic effects, anti-allergic effects, anti-rheumatic effects, anti-arteriosclerotic effects and anti-inflammatory effects.
With the foregoing circumstances in mind, the present inventors carried out an extensive investigation to find a substance which inhibits cell adhesion and cell infiltration. As a result, we found that compounds represented by the general formula (1) have excellent cell adhesion-inhibiting effects and cell infiltration-inhibiting effects and are useful as anti-allergic agents, anti-asthmatic agents, anti-rheumatic agents, anti-arteriosclerotic agents or anti-inflammatory agents.
The present invention provides a piperazine compound represented by the following general formula (1): 
wherein X is xe2x80x94CH2xe2x80x94, xe2x80x94C(O)xe2x80x94 or xe2x80x94CH(CH3)xe2x80x94; R1 is a hydrogen atom or alkyl group; and R2 is a hydrogen atom, alkyl group, hydroxyalkyl group, arylalkyl group, heteroarylalkyl group, carboxyalkyl group, carboxamidoalkyl group, aminoalkyl group or guanidinoalkyl group;
an acid-addition salt thereof, or a hydrate thereof.
According to the present invention, there is also provided a medicine comprising the above piperazine compound, the acid-addition salt thereof, or the hydrate thereof as an active ingredient.
According to the present invention, there is further provided a medicinal composition comprising the above piperazine compound, the acid-addition salt thereof, or the hydrate thereof and a pharmaceutically acceptable carrier.
According to the present invention, there is still further provided a method for treating a disease caused by cell adhesion and/or cell infiltration, which comprises administering an effective amount of the above piperazine compound, the acid-addition salt thereof, or the hydrate thereof to a patient who requires the treatment.
The alkyl groups represented by R1 and R2 are preferably C1-C6-alkyl groups, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl and hexyl groups, with methyl, ethyl, n-propyl, isopropyl, isobutyl and sec-butyl groups being particularly preferred.
The hydroxyalkyl group represented by R2 is a hydroxy-C1-C6-alkyl group, and specific examples thereof include hydroxymethyl, 2-hydroxyethyl, 2-hydroxy-1-methylethyl, 2-hydroxy-1,1-dimethylethyl, 3-hydroxypropyl, 3-hydroxy-2-methylpropyl, 4-hydroxybutyl, 5-hydroxypentyl and 6-hydroxyhexyl groups, with hydroxymethyl, 2-hydroxyethyl, 2-hydroxy-1-methylethyl, 2-hydroxy-1,1-dimethylethyl and 3-hydroxypropyl groups being particularly preferred. The arylalkyl group is preferably a C6-C10-aryl-C1-C6-alkyl groups, and specific examples thereof include phenyl-C1-C6-alkyl groups such as benzyl and phenethyl groups. The heteroarylalkyl group is preferably a 5- or 6-membered heteroaryl-C1-C6-alkyl group having 1 or 2 nitrogen atoms, and preferable examples thereof include pyridyl-C1-C6-alkyl groups, pyrimidyl-C1-C6-alkyl groups, imidazolyl-C1-C6-alkyl groups and pyrrolyl-C1-C6-alkyl groups. The carboxyalkyl group is preferably a carboxy-C1-C6-alkyl group, and specific examples thereof include carboxymethyl and carboxyethyl groups. The carboxamidoalkyl group is a carboxamido-C1-C6-alkyl group, and specific examples thereof include carboxamidomethyl and carboxamidoethyl. The aminoalkyl group is preferably a amino-C1-C6-alkyl group, and specific examples thereof include aminomethyl, aminoethyl and aminopropyl groups. The guanidinoalkyl group is preferably a guanidino-C1-C6-alkyl group, and specific examples thereof include guanidinomethyl, guanidinoethyl and guanidinopropyl groups.
No particular limitation is imposed on the acid-addition salts of the compounds (1) according to the invention as long as they are pharmaceutically acceptable salts. Examples include the acid-addition salts of mineral acids, such as hydrochlorides, hydrobromides, hydriodides, sulfates and phosphates; and acid-addition salts of organic acids, such as benzoates, methanesulfonates, ethanesulfonates, benzenesulfonates, p-toluenesulfonates, oxalates, maleates, fumarates, tartrates, citrates and acetates.
The compounds of formula (1) may be present in the form of solvates typified by hydrates, and the solvates are embraced in the present invention. Optical isomers are present in the compounds (1) according to the present invention, and all the isomers are also embraced in the present invention.
Among the compounds (1) those in which X is xe2x80x94CH(CH3)xe2x80x94 or xe2x80x94CH2xe2x80x94 can be prepared in accordance with, for example, a process shown in the following reaction formula: 
wherein X is xe2x80x94CH (CH3)xe2x80x94 or xe2x80x94CH2xe2x80x94, and R1 and R2 have the same meanings as defined above.
More specifically, a chlorinated compound (2) is reacted with 3,4,5-trimethoxyphenylboronic acid (3) at 0xc2x0 C. to reflux temperature, preferably 90xc2x0 C. for 10 minutes to several days, preferably 5 hours in the presence of a metal catalyst such as tetrakis(triphenylphosphine)palladium(0) and a base such as 2 M sodium carbonate in a solvent such as toluene, benzene, tetrahydrofuran (THF) , dioxane or acetonitrile, thereby obtaining a condensate (4). This compound is reacted with lithium aluminum hydride at xe2x88x9220xc2x0 C. to room temperature, preferably at 0xc2x0 C. for several seconds to several hours, preferably 30 minutes in THF, thereby giving an alcohol (5). The compound (5) is stirred together with thionyl chloride at xe2x88x9220xc2x0 C. to room temperature, preferably 0xc2x0 C. for 1 hour to several days, preferably 5 hours in a solvent such as chloroform, dichloromethane, ethyl acetate, ether, THF or dioxane, thereby obtaining a chloro-derivative (6). The compound (6) and a diamine (7) are stirred at room temperature to 100xc2x0 C., preferably 50xc2x0 C. for 1 hour to several days, preferably 5 hours in the presence of potassium carbonate in a solvent such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) or acetonitrile, thereby obtaining a compound (1a) according to the present invention.
Among compounds (1), those in which X is xe2x80x94C(O)xe2x80x94 can be prepared in accordance with, for example, a process shown in the following reaction formula: 
wherein X is xe2x80x94C(O)xe2x80x94, and R1 and R2 have the same meanings as defined above.
More specifically, a glycine methyl ester (8) is reacted with 2-nitrobenznesulfonyl chloride in accordance with an already known method, thereby obtaining a 2-nitrobenzenesulofonylated compound (9). The above-described chloro-derivative (6) is reacted with the compound (9) under the same conditions as described above to obtain a compound (10). The compound (10) is treated by an already known method, thereby obtaining a compound (11). The compound (11) is reduced by lithium aluminum hydride under the same conditions as described above, thereby obtaining an alcohol (12). The compound (12) is reacted with tert-butyldimethylsilyl chloride (TBDMS-Cl) at 0xc2x0 C. to reflux temperature, preferably 50xc2x0 C. for 1 hour to several days, preferably a night in the presence of a base such as imidazole, triethylamine or 4-methylmorpholine and 4-(dimethylamino)pyridine in a solvent dichloromethane, acetonitrile or DMF to obtain a TBDMS-derivative (13). The compound (13) is reacted with 9-fluorenylmethoxycarbonyl-amino acid (Fmoc-amino acid) (14) at 0xc2x0 C. to reflux temperature, preferably room temperature for 1 minute to several days, preferably 10 minutes in the presence of a dehydration-condensing agent such as dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (water-soluble carbodiimide hydrochloride) or O-(1H-benzotriazol-1-yl)-N,N,Nxe2x80x2,Nxe2x80x2-tetramethyluronium hexafluorophosphate (HBTU) in a solvent such as chloroform, dichloromethane, acetonitrile, THF, DMF or DMSO, thereby obtaining a compound (15). The compound (15) is reacted with piperidine in accordance with an already known method, thereby obtaining an amine derivative (16). The compound (16) is reacted with the above-described 2-nitrobenzenesulfonyl chloride under the same conditions as described above to obtain a 2-nitrobenzenesulfonylated compound (17). The compound (17) is treated by an already known method, thereby obtaining an alcohol (18). The compound (18) is dissolved in a solvent such as THF or dioxane and reacted with triphenylphosphine and diethyl azodicarboxylate (DEAD) at 0xc2x0 C. to reflux temperature, preferably room temperature for 1 hour to several days, preferably a night, thereby obtaining a compound (19). The compound (19) is subjected to de-2-nitrobenzenesulfonylation by an already known method to obtain a compound (20). The above-described chloro-derivative (6) is reacted with the compound (20) under the same conditions as described above, thereby obtaining a compound (1b) according to the present invention.
Among the compounds (1) according to the present invention, those in which X is xe2x80x94CH2xe2x80x94 can be prepared in accordance with, for example, a process shown in the following reaction formula: 
wherein X is xe2x80x94CH2xe2x80x94, and R1 and R2 have the same meanings as defined above.
More specifically, an N-benzylglycine methyl ester (21) is reacted with Fmoc-amino acid (22) in accordance with an already known method, thereby obtaining a dipeptide derivative (23). The compound (23) is subjected to de-Fmoc and cyclization at the same time in accordance with an already known method to obtain a diketopiperazine derivative (24). The compound (24) is treated by an already known reduction method making use of lithium aluminum hydride or the like, thereby obtaining a piperazine derivative (25). The compound (25) is subjected to de-benzylation by already known catalytic reduction making use of palladium on carbon, thereby obtaining a compound (26). The compound (26) is reacted with the above-described chloro-derivative (6) under the same conditions as described above, thereby obtaining a compound (1c) according to the present invention.
The compounds (1) according to the present invention are obtained by any of the above-described processes and may further be purified by using an ordinary purification means such as recrystallization or column chromatography as needed. As needed, the compounds may also be converted into the desired salts or solvates in a method known per se in the art. When the compounds (1) include configurational isomers, the present invention include any isomers.
The compounds (1) according to the present invention, or acid-addition salts or solvates thereof thus obtained have an excellent inhibitory effect of cell adhesion as demonstrated in the Examples, which will be described subsequently, and are useful as medicines for treatment or prevention of diseases of animals including human, such as asthma, allergy, rheumatism, arteriosclerosis and inflammation.
The medicine according to the present invention comprises a compound (1), a salt thereof, or a solvate thereof as an active ingredient. The form of administration may be suitably selected as necessary for the therapeutic application intended without any particular limitation, including oral preparations, injections, suppositories, ointments, inhalants, eye drops, nose drops and plasters. A composition suitable for use in these administration forms can be prepared by blending a pharmaceutically acceptable carrier in accordance with the conventional preparation method publicly known by those skilled in the art.
When an oral solid preparation is formulated, an excipient, and optionally, a binder, a disintegrator, a lubricant, a colorant, a taste corrigent, a smell corrigent and the like are added to compound (1), and the resultant composition can be formulated into tablets, coated tablets, granules, powders, capsules, etc. in accordance with methods known in the art.
As such additives described above, any additives may be used which are generally used in the pharmaceutical field. Examples thereof include excipients such as lactose, sucrose, sodium chloride, glucose, starch, calcium carbonate, kaolin, microcrystalline cellulose and silicic acid; binders such as water, ethanol, propanol, simple syrup, glucose solution, starch solution, gelatin solution, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl starch, methyl cellulose, ethyl cellulose, shellac, calcium phosphate and polyvinyl pyrrolidone; disintegrators such as dry starch, sodium alginate, agar powder, sodium hydrogencarbonate, calcium carbonate, sodium lauryl sulfate, monoglyceryl stearate and lactose; lubricants such as purified talc, stearic acid salts, borax and polyethylene glycol; and taste corrigents such as sucrose, orange peel, citric acid and tartaric acid.
When an oral liquid preparation is formulated, a taste corrigent, buffer, stabilizer, smell corrigent and/or the like are added to compound (1), and the resulting composition can be formulated into internal liquid preparations, syrup preparations, elixirs, etc. in accordance with methods known in the art. In this case, vanillin as the taste corrigent, may be used. As the buffer, sodium citrate may be mentioned. As examples of the stabilizer, tragacanth, gum arabic and gelatin may be mentioned.
When an injection is formulated, a pH adjustor, buffer, stabilizer, isotonicity agent, local anesthetic and the like may be added to the compound (1) according to the present invention, and the resulting composition can be formulated into subcutaneous, intramuscular and intravenous injections in accordance with methods known in the art. Examples of the pH adjustor and buffer in this case include sodium citrate, sodium acetate and sodium phosphate. Examples of the stabilizer include sodium pyrosulfite, EDTA, thioglycolic acid and thiolactic acid. Examples of the local anesthetic include procaine hydrochloride and lidocaine hydrochloride. Examples of the isotonicity agent include sodium chloride and glucose.
When a suppository is formulated, a carrier preparation known in the art, for example, polyethylene glycol, lanoline, cacao butter, fatty acid triglyceride or the like, and optionally, a surfactant such as Tween (trade mark) and the like are added to the compound (1), and the resultant composition can be formulated into suppositories in accordance with methods known in the art.
When an ointment is formulated, a base material, stabilizer, wetting agent, preservative and the like, which are generally used, are blended with compound (1) as needed, and the resulting blend is mixed and formulated into ointments in accordance with known methods. Examples of the base material include liquid paraffin, white vaseline, bleached beeswax, octyldodecyl alcohol and paraffin. Examples of the preservative include methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate and propyl p-hydroxybenzoate.
Besides the above preparations, inhalants, eye drops and nose drops may also be formulated in accordance with known methods.
The dose of the medicine according to the present invention varies according to the age, weight and condition of the patient to be treated, the administration method, the number of times of administration, and the like. It is however preferred that the medicine is generally orally or parenterally administered at once or in several portions in a dose of 1 to 1,000 mg per day in terms of compound (1), for an adult.
The present invention will hereinafter be described in more detail by Examples. However, the present invention is not limited to these examples.